Hi Everyone,
My biology teacher got me thinking today when she rhetorically asked what Earth would be like today if water didn't expand when it was frozen. I just wondered what other folks came up with.
Thanks so much!

It would be tough for marine and freshwater life to survive since floating ice has insulating properties on the body of water over which it floats. Ice that sinks would push fish higher and higher into colder and colder water that would kill them. Thats just one thing, I'm sure there are other advantages. Though, sinking ice would be good in my glass of lemonade so it doesn't block flow into my mouth.....

-Jelanen

'It is futile to pretend to the public that we understand how an amoeba evolved into a man, when we cannot tell our students how a human egg produces a skin cell or a brain cell!'

Well, yeah. There are many aspects of waters unique properties that would completely change the world we know if it was different.

But one thing comes instantly to mind that I think is by far the MOST significant aspect. It requires some explanation (for those who don't already know) about the reasons why ice is less dense then liquid water.

As we all know water is two hydrogen and one oxygen atom. H20, right? Now the interesting thing about this bond is that hydogen only has one electron, so when the two hydrogens bond with oxygen, which has a high affinity for these electrons, it takes hold of these electrons so that they spend most of their time in the area closest to the oxygen atom. This creates a difference in charge between the oxygen end of the molecule and the hydrogen end because the hydrogen attoms now have an exposed nucleus which is highly positive. If it was any other atom that was sharing it's valence electron the difference would be less, but hydrogen only has one electron so when it shares it the nucleus becomes exposed. This is a very important trait and is given it's own name as hydrogen bonding. The significance is H20 is polar liquid, and the molecules tend to want to stay together due to their attraction to each other. Basically H20 is a very unique substance. We can attribute it's specific heat to the polarity of its molecules and the density of ice is lower because as the molecules slow down the arrange themselves into a crystaline structure that occupies more space then the liquid itself.

Anyway, I just wanted to ramble I guess. Once again, water is amazing. That tricky little hydrogen with it's exposed nucleus causing dipole polarities. Sweat a little, cool down, you owe it to those interesting chemical properties of H20!

That is a perfect explanation. I couldn't agree more with that statement. I, not being as creative as you guys, and limited to help others with their explanations with the seven properties of water and one unique characteristic:
1. High Specific Heat
2. Attracts Polar Molecules
3. Sticks to Nonpolar Molecules ex. Water sticking to straw on the way down after inhaling results in water not quickly flowing from straw
4. Surface Tension
5. Adhesion
6. Cohesion
7. Capillary Action
and the special ability is water acts as a buffer
(If your not sure of some of these, or even one, look it up, just search water properties and click on the first link)

Saying that any two humans are exactly alike is like saying republicans have morals

If water sank and in turn there would be not Polar ice caps which are immence in size there would also be no land. Water would cover everything. Anyone seen the movie waterworld... Then again without land humans would never have evolved therefore no question about what the world would be like if water didn't expand when it froze

It's crazy for me to think about this concept! Thanks everyone for your responses. I've decided to do a biology project on this, just for the fun of it and for extra marks. Please, feel free to keep adding circumstances and results to the list. I'd love to hear more!
Cheers!

One POSSIBLE result might be that ordinary plant or animal cells could be frozen and thawed without killing them. Since, I believe, the main reason for cell death during freazing is damage due to water expanding and rupturing cell walls, etc. Correct me if I'm wrong.

The weathering process would be hampered. There would be no frost-wedging, therefore mountains would likely be higher than they are now. Trans-atlantic travel would be safer, no more icebergs running down south into the shipping lanes. Penquins wouldn't have to travel so far each year to their breeding grounds. People living near the Great lakes couldn't move their ice-houses out each year to catch whatever it is they catch. The Cokes in my freezer wouldn't explode everywhere. Man, what a crazy world it would be!